This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Using a rhesus monkey model, this project is designed to provide a better understanding of how psychosocial stress, imposed by social subordination, affects brain maturations and emotional development in females and whether this is influenced by polymorphisms in the gene that encodes the serotonin re-uptake transporter (5HTT), a protein essential for normal serotonin neurotransmission and emotionality. In this initial of the project, the first cohort of animals were recruited. These animals are embedded in large social groups at the Field Station and are distributed throughout the social status hierarchy of each group. In addition, 19 animals have the l/l 5HTT genotype and 20 animals have the l/s or s/s 5HTT genotype. Studies began this year included a dexamethasone suppression test to assess glucocorticoid negative feedback;measures of activity using a device (Actical) worn by the animal;tests of emotionality using the approach/avoidance test;and neuroimaging of the serotonin (5HT) 1A receptor using PET. These studies will elucidate the complex interplay between behavior, genetics, and reproductive maturation, providing a comprehensive understanding of how adolescence represents a critical period for the emergence of psychiatric disorders.